Merge tag 'timers-nohz-2026-06-13' of gitolite.kernel.org:pub/scm/linux/kernel/git...

Pull NOHZ updates from Thomas Gleixner:

 - Fix a long standing TOCTOU in get_cpu_sleep_time_us()

 - Make the CPU offline NOHZ handling more robust by disabling NOHZ on
   the outgoing CPU early instead of creating unneeded state which needs
   to be undone.

 - Unify idle CPU time accounting instead of having two different
   accounting mechanisms. These two different mechanisms are not really
   independent, but the different properties can in the worst case cause
   that gloabl idle time can be observed going backwards.

 - Consolidate the idle/iowait time retrieval interfaces instead of
   converting back and forth between them.

 - Make idle interrupt time accounting more robust. The original code
   assumes that interrupt time accouting is enabled and therefore stops
   elapsing idle time while an interrupt is handled in NOHZ dyntick
   state. That assumption is not correct as interrupt time accounting
   can be disabled at compile and runtime.

 - Fix an accounting error between dyntick idle time and dyntick idle
   steal time. The stolen time is not accounted and therefore idle time
   becomes inaccurate. The stolen time is now accounted after the fact
   as there is no way to predict the steal time upfront.

* tag 'timers-nohz-2026-06-13' of gitolite.kernel.org:pub/scm/linux/kernel/git/tip/tip:
  sched/cputime: Handle dyntick-idle steal time correctly
  sched/cputime: Handle idle irqtime gracefully
  sched/cputime: Provide get_cpu_[idle|iowait]_time_us() off-case
  tick/sched: Consolidate idle time fetching APIs
  tick/sched: Account tickless idle cputime only when tick is stopped
  tick/sched: Remove unused fields
  tick/sched: Move dyntick-idle cputime accounting to cputime code
  tick/sched: Remove nohz disabled special case in cputime fetch
  tick/sched: Unify idle cputime accounting
  s390/time: Prepare to stop elapsing in dynticks-idle
  powerpc/time: Prepare to stop elapsing in dynticks-idle
  sched/cputime: Correctly support generic vtime idle time
  sched/cputime: Remove superfluous and error prone kcpustat_field() parameter
  sched/idle: Handle offlining first in idle loop
  tick/sched: Fix TOCTOU in nohz idle time fetch

diff --cc drivers/cpufreq/cpufreq.c
Simple merge

diff --cc drivers/cpufreq/cpufreq_governor.c
index 8a85bd32defe7a8d4e8a849c00088d9d6417ea34,3c4a1f9af3ae822497be8bbda19abeb21cacf248..710d93ec89b5334a4d95065ec0fee262b3befa3f
--- 1/drivers/cpufreq/cpufreq_governor.c
--- 2/drivers/cpufreq/cpufreq_governor.c
+++ b/drivers/cpufreq/cpufreq_governor.c
@@@ -112,9 -104,9 +112,9 @@@ void gov_update_cpu_data(struct dbs_dat
  
                        j_cdbs->prev_cpu_idle = get_cpu_idle_time(j, &j_cdbs->prev_update_time,
                                                                  dbs_data->io_is_busy);
-                       j_cdbs->prev_cpu_nice = kcpustat_field(&kcpustat_cpu(j), CPUTIME_NICE, j);
 -                      if (dbs_data->ignore_nice_load)
 -                              j_cdbs->prev_cpu_nice = kcpustat_field(CPUTIME_NICE, j);
++                      j_cdbs->prev_cpu_nice = kcpustat_field(CPUTIME_NICE, j);
                }
 +              mutex_unlock(&policy_dbs->update_mutex);
        }
  }
  EXPORT_SYMBOL_GPL(gov_update_cpu_data);
@@@ -173,18 -164,12 +173,18 @@@ unsigned int dbs_update(struct cpufreq_
  
                j_cdbs->prev_cpu_idle = cur_idle_time;
  
 -              if (ignore_nice) {
 -                      u64 cur_nice = kcpustat_field(CPUTIME_NICE, j);
 -
 +              /*
 +               * Always sample cur_nice and advance prev_cpu_nice, regardless
 +               * of ignore_nice.  This keeps prev_cpu_nice current so that
 +               * enabling ignore_nice_load via sysfs never produces a
 +               * stale-baseline spike (the delta will be at most one sampling
 +               * interval of accumulated nice time, not since boot).
 +               */
-               cur_nice = kcpustat_field(&kcpustat_cpu(j), CPUTIME_NICE, j);
++              cur_nice = kcpustat_field(CPUTIME_NICE, j);
 +              if (ignore_nice)
                        idle_time += div_u64(cur_nice - j_cdbs->prev_cpu_nice, NSEC_PER_USEC);
 -                      j_cdbs->prev_cpu_nice = cur_nice;
 -              }
 +
 +              j_cdbs->prev_cpu_nice = cur_nice;
  
                if (unlikely(!time_elapsed)) {
                        /*
@@@ -552,9 -537,10 +552,9 @@@ int cpufreq_dbs_governor_start(struct c
                 * Make the first invocation of dbs_update() compute the load.
                 */
                j_cdbs->prev_load = 0;
-               j_cdbs->prev_cpu_nice = kcpustat_field(&kcpustat_cpu(j), CPUTIME_NICE, j);
 -
 -              if (ignore_nice)
 -                      j_cdbs->prev_cpu_nice = kcpustat_field(CPUTIME_NICE, j);
++              j_cdbs->prev_cpu_nice = kcpustat_field(CPUTIME_NICE, j);
        }
 +      mutex_unlock(&policy_dbs->update_mutex);
  
        gov->start(policy);
  

diff --cc fs/proc/stat.c
index 20c3df9a9b800316c88bd8b88750377d71b3e759,c00468a83f64b58d1d58341a9a02d7368f3c6e90..79b42f2bfd000560b5fbb39104d0171113ed29e3
--- 1/fs/proc/stat.c
--- 2/fs/proc/stat.c
+++ b/fs/proc/stat.c
@@@ -18,39 -18,10 +18,7 @@@
  #ifndef arch_irq_stat_cpu
  #define arch_irq_stat_cpu(cpu) 0
  #endif
 -#ifndef arch_irq_stat
 -#define arch_irq_stat() 0
 -#endif
  
- u64 get_idle_time(struct kernel_cpustat *kcs, int cpu)
- {
-       u64 idle, idle_usecs = -1ULL;
- 
-       if (cpu_online(cpu))
-               idle_usecs = get_cpu_idle_time_us(cpu, NULL);
- 
-       if (idle_usecs == -1ULL)
-               /* !NO_HZ or cpu offline so we can rely on cpustat.idle */
-               idle = kcs->cpustat[CPUTIME_IDLE];
-       else
-               idle = idle_usecs * NSEC_PER_USEC;
- 
-       return idle;
- }
- 
- static u64 get_iowait_time(struct kernel_cpustat *kcs, int cpu)
- {
-       u64 iowait, iowait_usecs = -1ULL;
- 
-       if (cpu_online(cpu))
-               iowait_usecs = get_cpu_iowait_time_us(cpu, NULL);
- 
-       if (iowait_usecs == -1ULL)
-               /* !NO_HZ or cpu offline so we can rely on cpustat.iowait */
-               iowait = kcs->cpustat[CPUTIME_IOWAIT];
-       else
-               iowait = iowait_usecs * NSEC_PER_USEC;
- 
-       return iowait;
- }
- 
  static void show_irq_gap(struct seq_file *p, unsigned int gap)
  {
        static const char zeros[] = " 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0";

diff --cc kernel/rcu/tree.c
Simple merge

diff --cc kernel/time/tick-sched.c
Simple merge